hash-wallet/lib/test_asset_bundles.dart

import 'dart:convert';

import 'package:flutter/services.dart';

class TestAssetBundle extends CachingAssetBundle {
  @override
  Future<String> loadString(String key, {bool cache = true}) async {
    final ByteData data = await load(key);

    return utf8.decode(data.buffer.asUint8List());
  }

  @override
  Future<ByteData> load(String key) async => rootBundle.load(key);
}